At present, a nuclear island primary loop coolant circulating pump (nuclear main pump for short) is the key equipment of the nuclear power plant. The nuclear main pump plays a vital role on the operation and safety of the entire nuclear power plant, while a bearing of the nuclear main pump is a key component to ensure that the circulating pump operates safely and reliably.
Bearings of nuclear main pumps configured for small-capacity generator units of nuclear power plants at home and abroad are water lubricated thrust bearings made of graphite materials. The structure of the water lubricated thrust bearing is that a graphite plate is placed in a clamping groove of a sector-shaped steel tile base and two sides of the graphite plate are fixed with baffle plates. As the graphite is a kind of brittle material which has poorer impact resistance, in the larger impact load and alternating load conditions, the tile is easy to break, poor in safety and reliability and not suitable for long-term safe operation of high-power nuclear main pumps. In addition, due to brittleness and poor adaptability, the graphite bearing material cannot adjust the uneven stress condition on the whole set of bearing and the single tile surface by itself and is prone to causing an unbalanced loading condition.
Secondly, the water lubricated thrust bearing is made of a metal plate and an engineering plastic plate using a mechanical combination structure. This structure is mounted and located by a clamping groove on the plane of the steel tile and fastened with bolts. Because this structure is mounted by splicing multiple layers of structures, the fastening screws and the bearing in the long-time running process have defects of loosening, falling and connection instability to increase accident points, thereby bringing potential safety hazards for the running of the nuclear main pump.
Nowadays, nuclear power gradually shifts to the development of large-capacity generator units. The prior art has not adapted to the use requirements of high-power nuclear main pumps, and nuclear main pump bearings have become the bottleneck in the development of large-capacity nuclear power equipment. Therefore, it is urgent to provide a thrust bearing for a high-power nuclear main pump, which is resistant to nuclear radiation and adapted to water lubrication, safe and reliable.